'Eve' Is the Root of All Plants

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'Eve' Is the Root of All Plants

Scientists mapping the relationships between plants say their research indicates that all green plant families have grown from a single ancestor. The announcement was made on Wednesday at the International Botanical Congress in St. Louis. Researchers working on the Deep Green project announced they have discovered that all green plants trace back in direct linear fashion to a common ancestor.

Deep Green, a six-year effort involving more than 200 plant biologists in 12 countries, said it has developed a framework for identifying the relationships between all the green plants on earth.

"The goal is to have a very complete picture of the tree of life," said Brent D. Mishler, a co-principal investigator for the project as well as a professor of integrative biology and director of the University and Jepson Herbaria at the University of California, Berkeley.

"Just as an artist starts with a sketch and then fills in the details, we now have the basic framework and can begin digging into the finer and finer scale."

It was previously thought that throughout history various families would have evolved and left descendants, so that today we would see distinct subgroups related only in the distant past, explained Mishler. Instead, at each stage of evolution only one family or lineage seems to have survived.

"It seems that only one lineage actually made it," Mishler said. "This indicates there's an Eve in the primordial soup."

"It's critical for understanding the evolutionary relationships among the green plants so that we can make intelligent assessments about scientific issues and conservation issues."

According to Mishler, understanding the interrelationships of plants will help scientists predict which plants might have qualities such as medicinal value or pest resistance.

"If you have an organism that's potentially harmful or helpful, the most useful thing is to know its relationships; this will help you predict its traits," said Mishler. "If you're looking for a cure for cancer, you don't want to go out randomly and look at every plant in the forest."Until recently, most biological study has taken place in relative isolation, with individual laboratories examining specific life forms – without a consistent mechanism to interrelate data.

But the Deep Green project (officially known as the Green Plant Phylogeny Research Coordination Group) has charted in detail the genetic relationships of 100 green plants representing all the major branches of the green plant world.

The project is jointly funded by the National Science Foundation, the US Department of Energy, and the Department of Agriculture.

In the future, the group plans to fill in the "twigs of those branches," said Mishler, with the eventual goal of mapping out the relationships between all green plants.

Deep Green plans to share its methodology and technology with scientists studying the other four major kingdoms: red plants, brown plants, fungi, and animals.

Crucial to the project was the role of new technologies. Advances in gene sequencing technologies allow data to be quickly compiled.

But even more important, said Mishler, was the Internet and parallel-processing computers.

"The phylogenies of this scale couldn't even be considered until computer hardware was complex enough to handle the algorithmic problems of building these trees of interrelationship," said Mishler. "The possible branching phylogenic trees for a few hundred species would be more than the number of atoms in the universe."

Furthermore, the presentation of the interrelationships would have been all but impossible on paper.

"There's no way to present this in a flat, linear text-based way; hypertext is the only way to really do it," said Mishler.

To coordinate the effort, Mishler and company faced cultural challenges within the field. Traditionally, plant biologists have worked "in a kind of tribal culture," alone or in small labs, and have carefully guarded their research out of fear of being scooped, said Krishtalka.

"We had to convince people to share what they're doing," said Mishler. "There was a lot of duplication of effort out there, which is a waste.... Our field has had to make a transition from even five years ago, where the field was oriented to the individual investigator, toward a 'big science' approach, wherein collaboration takes place."

This cultural shift has implications beyond the Deep Green project, said Krishtalka.

"The grand questions of biodiversity and biocomplexity will require interdisciplinary collaboration in a way that has never occurred before, and this project certainly advances toward that."